External eye diseases such as blepharoconjunctivities, meibomian gland dysfunction, and chalazia are common causes of chronic ocular disease and irritation. In recent years, it has become apparent that abnormalities in meibomian gland lipids may play a significant role in the pathophysiology of such ocular problems. The ultimate objective of this study is to determine the role of meibomian gland lipids in such external eye diseases. We plan to utilize ultramicro techniques such as the combination of flame ionization detection (FID) with thin layer chromatography (TLC), i.e. (IATROSCAN TH-10) in the analysis of an aliquot (approximately 10 micrograms) of a very small sample (50 to 500 micrograms) of lipids obtainable from the meibomian glands of patients with such eye diseases. We will first examine meibomian gland lipids from "normals" and then compare these findings with those from patients with various external eye diseases. At the present time, very little information is available concerning the role of meibomian gland lipids in ocular disease since the small amount of material available for study has not been sufficient to utilize standard lipid chemistry techniques. With the development of microtechniques as will by utilized in the present proposal, such studies are feasible as indicated by our studies during the first year of our current NEI-supported grant. In addition to disease states mentioned above, meibomian gland lipids are involved in tear film dynamics and contact lens wear problems, and these will be the subject of future investigations.